Direct Electrochemistry of Native and Denatured Anticancer Antibody Rituximab at a Glassy Carbon Electrode

Abstract

Rituximab (RTX) is a human/murine chimeric monoclonal antibody (mAb) that specifically targets the transmembrane protein CD20 of B-cells. The oxidation mechanism of native and denatured RTX was investigated on glassy carbon electrode. The denaturing agent sodium dodecyl sulfate and the redutancts tris(2-carboxyethyl)phosphine and dithiothreitol were used. Significant differences were observed for native and denatured RTX oxidation due to morphological changes and unfolding of the RTX native structure. Native RTX presented only one oxidation peak of tyrosine and tryptophan residues, whereas in denatured RTX were detected three peaks corresponding to the oxidation of tyrosine, tryptophan and histidine residues.

Effect of His6-tagging of anterior gradient 2 protein on its electro-oxidation

“…More than 30 years ago, oxidation (Y,W) signals were successfully applied for detection of different proteins [15,26,30,48]. Recently, changes in their structure such as denaturation, aggregation, phosphorylation have been studied using (Y,W) oxidation at carbon electrodes [12,15,[22][23][24][25].…”

“…Further studies of different proteins were in agreement with this work. Recently, oxidation of Met [22,33] and His [21,22] residues in proteins at carbon electrodes was reported but unambiguous experimental evidence of the origin of this oxidation is still needed. Very recently, His oxidation peak was not observed in His-containing angiotensin peptides at a basal plane pyrolytic graphite [32].…”

“…Besides analysis of non-protein part in conjugated proteins [19,20], predominantly, voltammetric oxidation peaks [15,[21][22][23][24][25] and/or chronopotentiometric catalytic peak H of proteins [13,17,18,26] were used for direct electrochemistry.…”

Cyclic Lipopeptide Antibiotic Daptomycin Electrochemical Oxidation at a Glassy Carbon Electrode

“…As denaturing agent, urea affects the secondary and tertiary structure without affecting the primary structure, the surfactant SDS dissolves hydrophobic proteins, and the reducing agent DTT disrupts disulphide bonds, which are essential for qualitative and quantitative analysis in proteomic mechanism investigation . Urea and SDS are not electroactive, unlike DTT, which is electroactive .…”

Quantitative Biodetection of Anticancer Drug Rituxan with DNA Biosensor Modified PAMAM Dendrimer/Reduced Graphene Oxide Nanocomposite

“…In the last decade electrochemical methods have been one of the significant techniques in the expansion of sensors and biosensors due to its advantages of inexpensive, simplicity, quick response, nondestructive detection and convenient for in‐situ detection. But it was found that due to the inflexibility of the RTX 3D structure, the electron transfers between the electroactive amino acids in the internal of the RTX 3D structure and the surface of electrode is more difficult and no electrical signal could appear from the interaction of the RTX on the electrode surface . So, in order to obtain an appropriate analytical signal for quantitative determination of RTX, we used the DNA biosensor.…”